The Stovebolt Site Forums The Shop Area Engine Shop 1954 Chevy 3100 engine swap .. hydramatic info needed

I am looking for some info on a engine swap I am doing.. I have a 1954 Chevy 3100 pickup with original Hydramatic auto transmission that the engine has no compression and I have a 235 out of a 1955 chevy that i want to swap in but need to know if anything is different ? like flywheel or anything else ? Thanks, Ben

Ben,

Your post title says 1954 3100 but your first sentence says 1953?

Welcome to Stovebolt.com

Let’s first confirm what year engine and transmission you have,

The Hydra-Matic transmission was first available In 1954 in a Chevrolet truck.
The H-M transmission was aligned to the original 235 engine that came with the transmission - they were matched and marked at the factory.

Do you have an ID plate on the transmission?
What code is on that plate?

What is your Engine Serial Number?
It is stamped into the block in the flat area at the rear of the engine.

Does your cab have a one-piece curved windshield, or does your cab have 2-pieces of flat glass windshield?

What is your Vehicle Serial Number that is stamped into a plate riveted/screwed to the cab driver’s side door opening, between the hinges. What is that serial number?

We have some members who are quite knowledgeable about the Hydra-Matic transmission.

You should be able to put the H-M behind the 55 235 if you check the runout adjustments to make sure transmission and engine are properly aligned to prevent balance issues.

As Tim mentioned above, the engine and transmission were a factory matched unit. I don’t know if it’s possible to separate them with any success. Those in the know will be along soon.

You can separate the engine and transmission somewhat easily.

But, as Greg posted above, you have to correctly align the transmission to the new engine. That is a complicated procedure that requires skill and experience.

We might have one or two members who have done that alignment?

If the engine and trans were originally installed as a unit, there should be a tag on the bellhousing adapter with the engine serial number stamped on it. That number will match the one stamped on the pad behind the distributor. If those numbers match, it's worth the cost of an engine rebuild just in collector's value to keep them together. Yes, the later engine and trans will probably mate up and run, but you'll probably end up with vibration, and possibly fluid leak problems.
Jerry

You can match up a replacement engine to a Hydra-matic transmission but it takes some special skills and tools.
You can read about it at the link below.
Flywheel housing alignment check
Face runout
Bore runout
http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm0794.html

You also should check the Torus cover runout.
http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm0762.html

Nowadays they make offset dowel pins to help align (dial indicate) the flywheel housing to the replacement engine.
As opposed to drilling, dial indicating and installing oversized dowel pins.

On the engine with no compression, what is the engine serial number that is located on a flat machined boss to the rear of the distributor?
The engine serial number should be some numbers then F54M or T54M.

sorry typo.. its a original 54 with auto trans and I have a 55 235 to go into it.. what I need to know is if the auto engine is any different than the manual trans engine.. Thanks, Ben

No difference mechanically, the only thing that would be different is the engine serial number.

The flywheel is part of the hydra-matic transmission. The torus cover bolts to the flywheel.
http://chevy.oldcarmanualproject.com/1929_57chevyparts/57cmpc0328.htm

You should ID the 1955 engine to make sure what you have.

I'm don't remember for sure, but I think the manual transmission uses two flywheel housing alignment dowel pins in the engine block.
Where as the hydra-matic transmission uses three flywheel housing alignment dowel pins.
If you separate the transmissions from the engines let us know how many dowel pins there are.
If you could post a picture of the dowel pins on both engines, that would be great.

This link is aligning the manual transmission housing.
Page 1
Page 2
After reading it looks like there are three flywheel housing alignment dowel pins used in the engine block for the manual trans.

Also check the pilot bushing/bearing in the back of the crankshaft. The H-M may have a bearing instead of the manual transmission bushing.